CVE-2026-59640

Medium

Description

In Bouncy Castle for Java before 1.85, OpenPGP CFB quick-check oracle active on symmetric/session-key paths. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bcpg-fips 1.0.13 (1.0.X series), 2.0.13 (2.0.X series) and 2.1.13 (2.1.X series).

SeverityMedium

CVSS5.3

Exploit probability28. percentile0.3%

ProductBouncycastle Bcpg-fips

PublishedAug 3, 2026

First seenAug 3, 2026

Weakness typeCWE-203CWE-203

How to fix

Update

bouncycastle bcpg-fips1.0.13, 2.0.13, 2.1.13 or later
bouncycastle bc-java1.85 or later

Patches

github.com/bcgit/bc-java/commit/6b94b1c146cec1f565d9a85847fae511af77503e

Vendor advisories

github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059640

Affected products

Product	Affected versions	Fixed in
bouncycastle bcpg-fips	v < 1.0.13, 2.0.8 ≤ v < 2.0.13, 2.1.10 ≤ v < 2.1.13	1.0.13, 2.0.13, 2.1.13
bouncycastle bc-java	v < 1.85	1.85
bouncycastle bouncy_castle_for_java_lts	v ≤ 2.73.11	—

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